Why no output?

Question

#include <iostream>
using namespace std;

int main()
{
#define root = 40;
for(int x = root, k = 0; x > 0, k > 0; x/=10, k++)
{
cout << k << endl;
}

return 0;
}

Answer 1

#include <iostream>
#define root 40;
using namespace std;

int main()
{
int k;
for(int x = root;k = 0,x > 0, k > 0, x/=10, k++)
{
cout << k << endl;
}

return 0;
}

Answer 2

I suggest you to read here https://en.cppreference.com/w/cpp/language/for

Answer 3

k = 0 isn't condition

Answer 4

The body of your for loop will be executed as long as “x > 0” and “k > 0” are true.

But initially k = 0, so the condition “k > 0” is false and the loop is exited.